Before panicked medical personnel in Oklahoma’s death chamber flipped down the blinds, witnesses saw a scene that one described as “incredibly difficult to watch”: the condemned man groaned, struggled, lifted his head, and said, “man” and “something’s wrong.”

Oklahoma’s first test of a new lethal drug combination failed disastrously Tuesday evening. Instead of a painless death, as intended, Clayton Lockett appeared to suffer. Gov. Mary Fallin said prison officials deny that Mr. Lockett ever regained consciousness before they administered a second dose of drugs intended to painlessly stop his breathing and his heart.

But on Wednesday she ordered an investigation into what happened. Preliminary testimony suggests there was a problem with the injection, not the drugs, state officials say.

The incident, which ended when Mr. Lockett died of a heart attack 43 minutes after the “cocktail” of three drugs was first injected, immediately raised legal challenges on Eighth Amendment grounds – that Oklahoma failed to protect Lockett from “cruel and unusual” punishment.

“I think everyone would recognize that this case fell short of [a humane] standard,” White House press secretary Jay Carney said during a regular briefing Wednesday.

But more broadly, the botched execution is raising questions about what society will accept in the course of states carrying out the death penalty, a punishment that a majority of Americans still support. One central question, legal experts say, is whether the current problems with lethal injections will pass or whether they might lead to deeper reviews of the death penalty.

“I don’t expect that this one incident will be in itself the straw that breaks the camel’s back and leads to the abolition of the death penalty, but clearly it was deeply troubling, and clearly a lot of people are going to be troubled by it,” says Rick Garnett, a law professor at the University of Notre Dame.

“Most Americans who support the death penalty still believe that it needs to be administered in a way that’s humane, and that’s possible, but difficult, to do,” he adds. “The conversation about what we the people are going to do will be affected by” botched executions like the one Tuesday in Oklahoma.

Lockett’s apparently painful death came only a few months after a convicted murderer and rapist in Ohio, Dennis McGuire, gasped and convulsed for 10 minutes after a lethal injection. Lethal injections should just take a few minutes to take effect and cause death.

Lockett, a convicted rapist, was on death row for shooting a woman, Stephanie Nieman, and then watching two confederates bury her alive.

The problems have arisen after the European Union in 2011 banned companies from selling drugs used in executions to American states. That has forced states to try new drugs and new suppliers. After new suppliers came under pressure for enabling executions, some states have agreed to keep suppliers' names confidential. This has raised questions about the quality of the drugs.

It has also forced states to come up with new lethal injection cocktails and procedures, and that has led to mistakes like the one in Oklahoma.

“Promoted as a more humane way to carry out the death penalty (Ronald Reagan once compared it putting a horse to sleep), the evidence shows that it’s nothing of the sort. The sheer complexity of lethal-injection protocols, furthermore, makes continued screw-ups almost inevitable,” writes Eli Lehrer, in the conservative National Review. “These errors cross the line into torture.”

Richard Ablow used even stronger language on Fox News, suggesting that Lockett’s “tortured death exposed the sinfulness of the death penalty and the amoral reasoning of those who support it.”

In many respects, such strong words are surprising. The death penalty is “part of the identity of our country … a tree deeply rooted in the ground,” says Deborah Denno, a professor at Fordham University School of Law in New York.

But the fact that Oklahoma botched another execution in January, when a convicted man complained that his body “was burning” after the drug injections – and that the White House weighed in Wednesday – makes this execution stand out, she says.

A lot attention had already been paid to Lockett’s execution because of the legal wrangling about Oklahoma's determination to keep its suppliers secret. Medical experts had warned that Oklahoma’s lethal injection cocktail was untested and likely to be “highly problematic,” Professor Denno says.

Others saw the botched process more as evidence of flaws in the lethal injection protocol, not the death penalty itself, which 6 out of 10 Americans still support on moral grounds.

“A botched execution in which death results only after the unanticipated and unintentional infliction of pain and suffering is an awful thing,” writes Andrew McCarthy, also in the conservative National Review. “It bears remembering, though, that the main objective of lethal injection is to render the death penalty as painless as possible – we are not talking here about criminal recklessness or depraved indifference to human life.”

A second inmate, Charles Warner, was scheduled to be executed in the same chamber on Wednesday, but his execution was stayed for two weeks by Governor Fallin after Tuesday's problems.